AS31 California Institute of Technology

CIT - California Institute of Technology · registered in the United States

IPv4 addresses131,84415 prefixes · 0.004% of announced IPv4

Rank in United States#479largest network in US by IPv4 space, of 18,338 · <0.01% of US

Rank worldwide#1,510of 79,396 networks with IPv4

IPv61 x /32 (65,536 x /48)3 prefixes

CountryUnited States18,679 ASNs registered there

Open AS31 in ASN lookup Look up an IP in this network (131.215.0.1) All networks in United States

IPv4 prefixes

All 15 prefixes, in address order.

131.215.0.0/17
131.215.128.0/18
131.215.192.0/19
131.215.224.0/21
131.215.232.0/23
131.215.234.0/24
131.215.235.0/24
131.215.236.0/22
131.215.240.0/20
134.4.0.0/16
137.164.3.74/31
137.164.3.204/31
192.12.19.0/24
192.31.43.0/24
192.41.208.0/24

IPv6 prefixes

All 3 prefixes.

2607:f380:1::118:9a40:34a0/123
2607:f380:1::118:9a40:3cc0/123
2607:f520::/32

Similar-sized networks in United States

ASNNameIPv4 addresses

AS13506#476 US-DEPARTMENT-OF-THE-TREASURY - United States Department of the Treasury132,096

AS6356#477 NERDCNET - University of Florida132,096

AS1556#478 DNIC-ASBLK-01550-01601 - United States Department of Defense (DoD)132,096

AS329#480 DNIC-ASBLK-00306-00371 - United States Department of Defense (DoD)131,840

AS5719#481 SUNYSB - State University of New York at Stony Brook131,840

AS2013#482 PACIFIC-GAS - PG&E131,840

IP-to-ASN data: iptoasn.com (public domain). Snapshot downloaded 2026-11-11, refreshed daily. Ranges are what each network announces in BGP, not registry allocations. Data sources